Tracheal stent

Abstract

The utility model discloses a tracheal stent, and belongs to the technical field of biomedical prostheses. The tracheal stent is of an open tubular structure with a U-shaped axial cross section, end lugs are arranged at two ports of the open tubular structure, supporting rods are arranged in the end lugs in a penetrating mode, small holes are formed in the tube wall of the open tubular structure, and the tracheal stent is similar to a tracheal cartilage ring. The flexible pipe can be folded and unfolded in the breathing process, the physiological function is met, the mechanical strength and deformation recovery of the flexible pipe can be improved through the end lugs and the supporting rods, and meanwhile tissue adhesion growth is facilitated through the small holes in the pipe wall.

Description

Technical Field

[0001] The utility model relates to a tracheal stent, in particular to a carbon-based material tracheal stent, belonging to the technical field of biomedical prostheses. Background Art

[0002] Clinically, due to tumors, trauma, etc., the resection of a long trachea has made it an inevitable trend to use artificial materials for reconstruction. However, due to the complexity of the tracheal tissue environment, there are many requirements for substitutes, which pose many challenges to artificial tracheal materials. For example, when transplanted into the body, it cannot achieve biological fusion and fixation with the body, and improper port connection may cause problems such as shedding, leakage, stenosis or infarction. There are also issues such as the restoration of tracheal dilation and contraction functions during the breathing process, and the permanent stability of the implant after the absence of the autologous trachea.

[0003] In the prior art, Chinese Patent (CN 100428919 C) discloses an artificial trachea, which uses a polytetrafluoroethylene porous tracheal prosthesis as the tracheal main body and combines titanium rings to achieve end connection. There is a large mass difference between the titanium ring and the autologous tissue, which will lead to atrophy of the autologous tissue and cause anastomotic dehiscence. Chinese Patent (CN 105056302 B) discloses an artificial trachea, which is made of 3D printing into a hollow tubular shaped structure and also faces the problem of end fixation. At the same time, it cannot achieve tracheal dilation and contraction during the breathing process. Chinese Patent (CN 105055060 B) discloses a tracheal stent using polycaprolactone (PCL) as a U-shaped ring, which has the problem of continued stenosis or failure due to the weakening of the tracheal tubular structure after the degradation of PCL. Summary of the Invention

[0004] Aiming at the defects existing in the prior art, the purpose of the utility model is to provide a tracheal stent, which has a structure similar to the tracheal cartilage ring. By designing an open tubular structure with a U-shaped axial cross-section, it can expand and contract during the breathing process, meeting the physiological functions. And through end ears and support rods, its mechanical strength and deformation recovery can be improved. At the same time, the small holes on the tube wall are beneficial for tissue adhesion and growth.

[0005] To achieve the above technical purpose, the utility model provides a tracheal stent, which has an open tubular structure 1 with a U-shaped axial cross-section. End ears 2 are provided at both ends of the open tubular structure, and support rods 6 are penetrated through the end ears. Small holes are provided on the tube wall of the open tubular structure.

[0006] The tracheal stent provided by the present utility model has a structure similar to that of a tracheal cartilage ring. By being designed as an open tubular structure with a U-shaped axial cross-section, it can expand and contract during the breathing process, meeting the physiological functions. Moreover, through the end ears and support rods, its mechanical strength and deformation recovery can be improved. For example, its tensile strength is greater than 150 MPa, its bending strength is greater than 80 MPa, and the cross-sectional expansion and contraction deformation amount is 0 - 40%. At the same time, the small holes provided on its tube wall are beneficial to tissue adhesion and growth.

[0007] As a preferred solution, the length of the open tubular structure is 6 - 12 cm, and the wall thickness is 0.2 - 1 mm. The length of the open tubular structure can be adjusted according to needs, and the wall thickness affects the mechanical properties of the tracheal stent. If the thickness is too thin, its mechanical strength will be affected, and if the thickness is too thick, its expansion and contraction function will be reduced.

[0008] As a preferred solution, in the U-shaped cross-section of the open tubular structure, the diameter of the arc segment is 15 - 30 mm, and the length of the straight segment is 5 - 20 mm. The design of the dimensions of the open tubular structure facilitates surface film covering and surgical operation, and can meet the clinical patient needs for different tracheal sizes.

[0009] As a preferred solution, the axial cross-section of the end ear is circular, and the inner diameter is 1 - 3 mm. The axial cross-sections of the end ears at both ends of the tracheal stent are circular. The end ears with this shape can avoid irritating the surrounding tissues and can also increase the bearing area at the ports.

[0010] As a preferred solution, the small holes on the tube wall include hole A3 and hole B4. The diameter of hole A is 2 - 4 mm, and the diameter of hole B is 0.4 - 1 mm; both hole A and hole B are arranged in rows of 3 - 10 holes and are evenly and alternately distributed along the axial direction of the tube wall. The aperture of hole A is larger, which is beneficial to the connection and fixation of the tracheal stent in the early stage, while the diameter of hole B is smaller, which is beneficial to the biological fixation of tissue compatibility in the later stage. Hole A and hole B are evenly distributed on the entire tube wall of the tracheal stent, which is more conducive to playing the role of the holes.

[0011] As a preferred solution, the open tubular structure has a carbon fiber composite material as the matrix, and a functional coating is provided on its surface, such as a pyrolytic carbon coating and / or a tantalum-doped diamond-like carbon coating. The carbon fiber composite material is a well-known material in the industry, which has carbon as the matrix and carbon fibers as the reinforcing phase. Using the carbon fiber composite material as the tracheal stent material has high strength, is non-degradable, has good supporting performance, and is durable. The surface of the tubular structure is provided with functional coatings such as pyrolytic carbon coatings or tantalum-doped diamond-like carbon coatings, which can endow the tracheal stent with good biocompatibility, while increasing the surface hardness and having a small friction coefficient. It is not only not easily damaged, but also can block the shedding of carbon-based particles, avoiding the black skin effect. At the same time, the tantalum-doped diamond-like carbon coating can provide radiopacity, which is beneficial for later diagnosis. The pyrolytic carbon coating and the tantalum-doped diamond-like carbon coating are both well-known coatings in the prior art and can be generated by existing well-known technologies.

[0012] As a preferred solution, the support rod is a carbon rod. Using a carbon rod as the support rod can improve the mechanical properties of the tracheal stent.

[0013] The tracheal stent provided by the present utility model is prepared by the following method:

[0014] 1) Weave carbon fibers into carbon fiber cloth with a surface density of 40 - 200 g / m 2 , a thickness of 0.2 - 1 mm, and then form at least one layer of carbon fiber cloth into an open tubular carbon fiber preform with a U-shaped cross-section, ears at both ends, and holes on the walls through a mold, with a carbon material rod passing through the ears.

[0015] 2) Subject the open tubular carbon fiber preform to chemical vapor deposition and / or liquid impregnation - pyrolysis to compound matrix carbon to form the required carbon fiber artificial tracheal stent blank;

[0016] The process of chemical vapor deposition for compounding matrix carbon is as follows: Place the open tubular carbon fiber preform in a deposition furnace, and at a temperature of 850 - 1300 °C, introduce a carbon-containing gas source (such as common gas carbon sources like natural gas, methane, propylene, etc.) and deposit for 10 - 100 h;

[0017] The process of liquid impregnation - pyrolysis for compounding matrix carbon is as follows: The carbon fiber preform is successively subjected to resin or pitch vacuum pressure impregnation, curing, and pyrolysis treatments: the impregnation pressure is 1.0 - 5.0 MPa, the impregnation time is 2 - 10 h; the curing temperature is 160 - 230 °C, the curing time is 10 - 50 h; the resin pyrolysis temperature is 900 - 1050 °C, the pressure is normal pressure, and the pyrolysis time is 2 - 20 h; the pitch pyrolysis temperature is 750 - 850 °C, the pressure is 50 - 200 MPa, and the impregnation time is 2 - 10 h;

[0018] 3) Machine process the carbon fiber carbon composite artificial tracheal stent blank, including cutting the ends and edges;

[0019] 4) Place the machined U-shaped artificial tracheal stent blank into a high-temperature furnace and heat it under vacuum or protective atmosphere conditions for impurity removal treatment (this step can be selected according to needs). The treatment conditions are: temperature 1500 - 2300 °C, heat preservation for 1 - 10 h;

[0020] 5) Prepare a pyrolytic carbon coating or / and a tantalum-doped diamond-like carbon coating on the surface of the carbon fiber artificial tracheal stent blank to obtain a carbon fiber carbon composite artificial tracheal stent; the pyrolytic carbon coating is generated by chemical vapor deposition, and the generation conditions are: using a gaseous carbon source (such as common gaseous carbon sources like natural gas, methane, propylene, etc.), depositing at a temperature of 900 - 1500 °C for 10 h - 50 h; the generation of the tantalum-doped diamond-like carbon coating, the generation conditions are: Ar gas flow rate is 20 - 100 sccm, acetylene gas flow rate is 10 - 100 sccm, vacuum degree is 1.0×10 -1 ~4.0×10 -1 Pa, ion source power is 0.5 - 3 kW, tantalum target power is 0.5 - 2 kW, tantalum target purity is not less than 99.9 wt%, workpiece negative bias voltage is 50 - 600 V, coating time is 1 - 5 h.

[0021] Compared with the prior art, the beneficial technical effects brought by the present utility model are:

[0022] 1) The tracheal stent is composed of a carbon fiber carbon composite material, which has high strength, does not degrade, has good supporting performance, and is durable.

[0023] 2) The tracheal stent is similar to the tracheal cartilage ring. By designing an open tubular structure with a U-shaped axial cross-section, it can expand and contract during the breathing process to meet the physiological functions.

[0024] 3) The end ears at both ends of the tracheal stent can avoid irritating the surrounding tissues and can also increase the bearing area of the port.

[0025] 4) The surface layer of the tracheal stent has a functional coating, which has good biocompatibility, high hardness, and a small friction coefficient. It is not only not easily damaged, but also can block the shedding of carbon-based particles and avoid the black skin effect.

[0026] 5) The surface of the tracheal stent can provide imaging properties by setting a tantalum-doped diamond-like carbon coating, which is beneficial for later diagnosis.

[0027] 6) The tracheal stent has excellent mechanical properties: tensile strength is greater than 150 MPa, bending strength is greater than 80 MPa, and the cross-sectional expansion and contraction deformation amount is 0 - 40%. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of a tracheal stent.

[0029] Figure 2 It is a schematic structural diagram of the axial cross-section of the tracheal stent.

[0030] Figure 3 It is a schematic top view structural diagram of the tracheal stent.

[0031] Figure 4 It is a schematic structural diagram of the axial cross-section of the end ears at both ends of the tracheal stent.

[0032] Among them, 1 is a tubular structure with a U-shaped axial cross-section, 2 is an end ear, 3 is hole A, 4 is hole B, 5 is a functional coating, and 6 is a support rod. Specific implementation manners

[0033] The following specific embodiments are intended to further illustrate the content of the present invention in conjunction with the accompanying drawings of the specification, rather than limiting the protection scope of the claims.

[0034] Embodiment 1

[0035] The specific structure of the tracheal stent provided in this embodiment is as Figures 1 to 4 shown. The tracheal stent structure has an open tubular structure with a U-shaped axial cross-section. The length of the open tubular structure is 10 cm, and the wall thickness is 0.3 mm. The diameter of the arc segment in the U-shaped cross-section of the open tubular structure is 20 mm, and the length of the straight segment is 10 mm. End ears are provided at both ends of the open tubular structure. The axial cross-section of the end ear is circular, with an inner diameter of 2 mm, and a carbon material support rod is penetrated through the end ear. Small holes are provided on the wall of the open tubular structure. The small holes include two types: hole A and hole B. The diameter of hole A is 3 mm, and the diameter of hole B is 0.5 mm; both hole A and hole B are arranged in a row of 7 holes and are evenly and alternately distributed along the axial direction of the wall. The entire tubular structure is made of carbon fiber carbon composite material, and a pyrolytic carbon coating and a tantalum-doped diamond-like carbon coating are sequentially provided on its surface.

[0036] The specific preparation method of the above-mentioned tracheal stent is as follows:

[0037] 1) Weave carbon fibers into carbon fiber cloth with a surface density of 60 g / m 2 , a thickness of 0.3 mm, and then use a mold to assist in making 2 layers of carbon fiber cloth into an open tubular carbon fiber preform with a U-shaped cross-section (the diameter of the arc segment is 20 mm, and the length of the straight segment is 10 mm), with ears at both ends and holes on the wall. A carbon material rod with a diameter of 2 mm is penetrated through the ear. Two types of holes, A and B, are provided on the wall. Among them, the diameter of hole A is 3 mm, which is beneficial for early connection and fixation, and the diameter of hole B is 0.5 mm, which is used for later biological tissue adhesion. Both hole A and hole B are arranged in a row of 7 holes and are evenly and alternately distributed along the axial direction of the wall.

[0038] 2) The tubular carbon fiber preform is composited with matrix carbon by chemical vapor deposition to make the required carbon fiber artificial tracheal stent blank; the process of chemical vapor deposition compositing matrix carbon is as follows: place the carbon fiber preform in a deposition furnace, introduce propylene at a temperature of 880 °C, and deposit for 50 h;

[0039] 3) The carbon fiber artificial tracheal stent blank is machined, including cutting the ends and edges, and the length of the blank is 10 cm;

[0040] 4) The machined U-shaped carbon fiber artificial tracheal stent blank is placed in a high-temperature furnace and heated under vacuum or protective atmosphere conditions for impurity removal treatment, and the treatment conditions are: temperature 1800 °C, holding time 3 h;

[0041] 5) After preparing a pyrolytic carbon coating and a tantalum-doped diamond-like carbon coating on the surface of the carbon fiber artificial tracheal stent blank, a carbon fiber carbon composite artificial tracheal stent is obtained; the pyrolytic carbon coating is generated by chemical vapor deposition, and the generation conditions are: using propylene, depositing at a temperature of 980 °C for 20 h; the tantalum-doped diamond-like carbon coating is generated, and the generation conditions are: Ar gas flow rate is 40 sccm, acetylene gas flow rate is 20 sccm, vacuum degree is 2.0×10 -1 Pa, ion source power is 1.5 kW, tantalum target power is 1 kW, Ta target purity is 99.9 wt%, workpiece negative bias voltage is 200 V, and coating time is 3 h.

Claims

1. A tracheal stent, characterized in that: The tracheal stent is an open tubular structure (1) with a U-shaped axial cross-section. End ears (2) are provided at both ends of the open tubular structure, and a support rod (6) is penetrated through the end ears; small holes are provided on the tube wall of the open tubular structure.

2. The tracheal stent according to claim 1, characterized in that: The length of the open tubular structure is 6-12 cm, and the wall thickness is 0.2-1 mm.

3. The tracheal stent according to claim 1 or 2, characterized in that: In the U-shaped axial cross-section of the open tubular structure, the diameter of the arc segment is 15-30 mm, and the length of the straight segment is 5-20 mm.

4. The tracheal stent according to claim 1, wherein: The axial cross-section of the end ear is circular, and the inner diameter is 1-3 mm.

5. The tracheal stent according to claim 1, characterized in that: The small holes on the tube wall include hole A (3) and hole B (4). The diameter of hole A is 2-4 mm, and the diameter of hole B is 0.4-1 mm; both hole A and hole B are arranged in rows of 3-10 holes and are evenly and alternately distributed along the axial direction of the tube wall.

6. The tracheal stent according to claim 1, 2 or 4, characterized in that: The open tubular structure uses a carbon fiber composite material as the matrix, and a functional coating (5) is provided on its surface.

7. The tracheal stent according to claim 1, wherein: The support rod is a carbon rod.

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